1. Technical Field
The disclosure generally relates to wireless communication devices, and particularly to a wireless communication device compatible with hearing aids.
2. Description of Related Art
In general, a hearing aid operates by using a microphone to pick up sound waves in the air and then converting the sound waves to electrical signals. The signals are then amplified as needed and converted back to audible sounds for the user. The hearing aid microphone, however, does not always work well in conjunction with audio devices such as mobile phones.
Mobile phones are often incompatible with hearing aids due to the potential for radio frequency (RF) interference in the form of scattered EM (electromagnetic) fields generated by the mobile phone while in use. When a mobile phone is in communication with its network, an electromagnetic field is present around the mobile phone. When the mobile phone is in use, the electromagnetic field generates pulses. It is this pulsing energy that may be picked up by the hearing aid's microphone, and heard as a buzzing sound (i.e., interference) by the user.
To deal with this situation, the United States Federal Communications Commission (FCC) has promulgated a hearing aid compatibility (HAC) standard to evaluate the interference intensity between a mobile phone and a hearing aid.
Referring to FIG. 7, the FCC defines HAC for mobile phones in terms of two parameters; radio-frequency (RF) emissions (M-scale) and telecoil coupling (T-scale). The M rating relates to the strength of the RF emissions from a mobile phone. The higher the M rating the mobile phone has, the lower the strength of the RF emissions, and the higher the quality of audio in the hearing aid. The T rating relates to a mobile phone's coupling ability. The higher the T rating awarded to the mobile phone, the more likely users will be able to use that mobile phone with the hearing aid.
In addition, to obtain a better transmission and reception capability, some mobile phones have a higher total radiated power (TRP). However, the M rating of the mobile phone may be reduced when the TRP is too high, and the mobile phone may be evaluated as incompatible with the hearing aid.
Therefore, there is room for improvement within the art.